Merge pull request #144 from TeigenZhang/pr/mouse-restore-decset-strip

feat(web): restore tap/click/wheel mouse interaction when server strips mouse DECSETs

src/web/public/index.html

@@ -560,6 +560,7 @@
             <div><kbd>Alt/Option</kbd>+<kbd>[</kbd> / <kbd>Alt/Option</kbd>+<kbd>]</kbd></div><div>Previous / Next Session</div>
             <div><kbd>Alt/Option</kbd>+<kbd>1-9</kbd></div><div>Switch to Tab N</div>
             <div><kbd>Ctrl</kbd>+<kbd>L</kbd></div><div>Clear Terminal</div>
+            <div><kbd>Shift</kbd>+<kbd>Wheel</kbd></div><div>Scroll local history (when mouse passthrough is active)</div>
             <div><kbd>Ctrl</kbd>+<kbd>+</kbd></div><div>Increase Font</div>
             <div><kbd>Ctrl</kbd>+<kbd>-</kbd></div><div>Decrease Font</div>
             <div><kbd>Ctrl</kbd>+<kbd>?</kbd></div><div>Show Help</div>

src/web/public/terminal-ui.js

@@ -353,13 +353,27 @@ Object.assign(CodemanApp.prototype, {
     // Register link provider for clickable file paths in Bash tool output
     this.registerFilePathLinkProvider();
 
-    // Always use mouse wheel for terminal scrollback, never forward to application.
-    // Prevents Claude's Ink UI (plan mode selector) from capturing scroll as option navigation.
+    // Mouse wheel: forward to the TUI only for sessions verified to handle SGR
+    // wheel reports (codex, and claude 2.1.187+ — see _shouldForwardWheelToApp),
+    // local scrollback otherwise. Claude Code 2.1.187+ scrolls its own
+    // transcript on SGR wheel reports — scrolled-away tool blocks re-render
+    // live and stay clickable — and its select menus no longer capture wheel
+    // as option navigation (verified against 2.1.202: /model menu highlight
+    // ignores wheel reports); older versions DO capture wheel as option
+    // navigation, so they keep the local wheel.
+    // Shift+wheel always scrolls xterm's local scrollback (Codeman's restored
+    // history lives there), and once the viewport left the bottom the wheel
+    // stays local until the user scrolls back down — so both scrollbacks stay
+    // reachable without a mode switch.
     container.addEventListener(
       'wheel',
       (ev) => {
         ev.preventDefault();
         const lines = Math.round(ev.deltaY / 25) || (ev.deltaY > 0 ? 1 : -1);
+        if (this._shouldForwardWheelToApp(ev)) {
+          this._sendSyntheticSgrWheel(ev.clientX, ev.clientY, lines);
+          return;
+        }
         this._noteTerminalUserScroll(lines);
         this.terminal.scrollLines(lines);
       },
@@ -482,6 +496,15 @@ Object.assign(CodemanApp.prototype, {
             }
             if (touch && mouseTrackingOn) {
               this._dispatchSyntheticTerminalClick(touch.clientX, touch.clientY);
+            } else if (touch && this._sessionUsesServerMouseStrip()) {
+              // The server strips mouse-tracking DECSETs from claude/codex/gemini
+              // output (isAltScreenStripMode, session.ts) so the wheel keeps
+              // scrolling scrollback — which leaves THIS xterm permanently at
+              // mouseTrackingMode 'none' even though the TUI on the PTY side has
+              // tracking ON and still understands SGR reports. Encode the report
+              // ourselves and send it straight to the PTY: no DOM click is
+              // dispatched, so xterm's local selection can't trigger either.
+              this._sendSyntheticSgrTap(touch.clientX, touch.clientY);
             }
             this._syncMobileHelperTextareaToCursor();
             // Route subsequent typing to the right place: keep the CJK input
@@ -508,6 +531,16 @@ Object.assign(CodemanApp.prototype, {
       );
     }
 
+    // ── Desktop click-to-position cursor ──────────────────────────────
+    // A real mouse click normally reaches the PTY through xterm's own mouse
+    // encoder, but that encoder only runs while mouseTrackingMode is ON — and
+    // the server strips the enabling DECSETs from claude/codex/gemini output
+    // (isAltScreenStripMode, session.ts) so the wheel keeps scrolling
+    // scrollback. Desktop clicks therefore stopped reporting entirely (the
+    // same breakage the mobile touchend tap branch above works around).
+    // Hand-encode the SGR report for plain left-clicks on those sessions.
+    container.addEventListener('click', (ev) => this._handleDesktopTerminalClick(ev));
+
     // Welcome message
     this.showWelcome();
 
@@ -951,6 +984,12 @@ Object.assign(CodemanApp.prototype, {
             activate(_event, text) {
               window.open(text, '_blank', 'noopener,noreferrer');
             },
+            hover() {
+              self._linkHovered = true;
+            },
+            leave() {
+              self._linkHovered = false;
+            },
           });
         };
 
@@ -989,6 +1028,12 @@ Object.assign(CodemanApp.prototype, {
             activate(event, text) {
               self.openLogViewerWindow(text, self.activeSessionId);
             },
+            hover() {
+              self._linkHovered = true;
+            },
+            leave() {
+              self._linkHovered = false;
+            },
           });
         };
 
@@ -2128,6 +2173,135 @@ Object.assign(CodemanApp.prototype, {
     }
   },
 
+  // Mirror of the server's isAltScreenStripMode (session.ts): session modes whose
+  // output stream has mouse-tracking DECSET sequences stripped before reaching the
+  // browser. For these, xterm's live mouseTrackingMode is useless as a gate — the
+  // PTY-side TUI keeps tracking enabled, we just never see the enable sequence.
+  _sessionUsesServerMouseStrip() {
+    const mode = this.sessions?.get(this.activeSessionId)?.mode || 'claude';
+    return mode === 'claude' || mode === 'codex' || mode === 'gemini';
+  },
+
+  // True when xterm's viewport shows the live PTY screen (not scrolled up into
+  // local scrollback). SGR coordinates are only meaningful then: the TUI's
+  // screen is the bottom `rows` of the buffer, so a report computed from a
+  // scrolled-up viewport would hit-test a completely different row.
+  _terminalViewportAtBottom() {
+    const buf = this.terminal?.buffer?.active;
+    return !buf || buf.viewportY >= buf.baseY;
+  },
+
+  // Map a viewport point to a 1-based terminal cell the same way xterm maps a
+  // click: offset inside .xterm-screen divided by the rendered cell size,
+  // clamped to the grid. Returns null when the terminal isn't measurable yet.
+  _clientPointToCell(clientX, clientY) {
+    if (!this.terminal || !Number.isFinite(clientX) || !Number.isFinite(clientY)) return null;
+    const screen = this.terminal.element?.querySelector('.xterm-screen');
+    const cell = this.terminal._core?._renderService?.dimensions?.css?.cell;
+    if (!screen || !cell?.width || !cell?.height) return null;
+    const rect = screen.getBoundingClientRect();
+    const col = Math.max(1, Math.min(this.terminal.cols, Math.floor((clientX - rect.left) / cell.width) + 1));
+    const row = Math.max(1, Math.min(this.terminal.rows, Math.floor((clientY - rect.top) / cell.height) + 1));
+    return { col, row };
+  },
+
+  // Encode a tap as an SGR mouse report (press + release at button 0) and send it
+  // to the PTY directly, bypassing xterm's mouse encoder.
+  _sendSyntheticSgrTap(clientX, clientY) {
+    if (!this.activeSessionId) return;
+    if (!this._terminalViewportAtBottom()) return; // scrollback click → misfire, do nothing
+    const pos = this._clientPointToCell(clientX, clientY);
+    if (!pos) return;
+    this._sendInputAsync(this.activeSessionId, `\x1b[<0;${pos.col};${pos.row}M\x1b[<0;${pos.col};${pos.row}m`);
+  },
+
+  // True when a parsed CLI version string ('2.1.187' — banner-parsed on the
+  // server, delivered via session:cliInfo / SessionState.cliVersion) is known
+  // AND >= the minimum. Unknown or unparseable versions return false so
+  // callers keep the conservative behavior.
+  _cliVersionAtLeast(version, minimum) {
+    if (typeof version !== 'string') return false;
+    const parts = version.trim().replace(/^v/, '').split('.').map(Number);
+    if (parts.length !== 3 || parts.some((n) => !Number.isFinite(n))) return false;
+    const min = minimum.split('.').map(Number);
+    for (let i = 0; i < 3; i++) {
+      if (parts[i] !== min[i]) return parts[i] > min[i];
+    }
+    return true;
+  },
+
+  // Wheel forwarding gate for the container wheel handler: no Shift override,
+  // xterm's own encoder dormant, viewport at the bottom, and a TUI VERIFIED to
+  // scroll its transcript on SGR wheel reports: codex, or claude 2.1.187+
+  // (older Claude Code captures wheel as select-menu option navigation; an
+  // unknown version is treated as older). Gemini is a strip mode too but its
+  // wheel behavior is unverified, so it keeps the local wheel — taps/clicks
+  // are still forwarded for it (harmless no-ops at worst).
+  _shouldForwardWheelToApp(ev) {
+    if (ev.shiftKey) return false;
+    const mode = this.terminal?.modes?.mouseTrackingMode;
+    if (mode && mode !== 'none') return false;
+    const session = this.sessions?.get(this.activeSessionId);
+    const sessionMode = session?.mode || 'claude';
+    if (sessionMode === 'claude') {
+      if (!this._cliVersionAtLeast(session?.cliVersion, '2.1.187')) return false;
+    } else if (sessionMode !== 'codex') {
+      return false;
+    }
+    return this._terminalViewportAtBottom();
+  },
+
+  // Encode wheel ticks as SGR reports (button 64 = up, 65 = down) at the pointer
+  // cell. Reports are coalesced into one PTY write per ~40ms: a trackpad emits
+  // dozens of wheel events per second and each _sendInputAsync becomes a tmux
+  // send-keys on the server — unbatched, a single flick would spawn a process
+  // storm. Per-event tick count is capped (Claude applies its own scroll-speed
+  // multiplier and acceleration on top), and the queue is bounded so a wild
+  // scroll can't build a backlog that keeps scrolling after the finger stops.
+  _sendSyntheticSgrWheel(clientX, clientY, lines) {
+    if (!this.activeSessionId || !lines) return;
+    const pos = this._clientPointToCell(clientX, clientY);
+    if (!pos) return;
+    const btn = lines < 0 ? 64 : 65;
+    const ticks = Math.min(Math.abs(lines), 5);
+    const queued = this._wheelSgrQueue || '';
+    if (queued.length > 512) return;
+    this._wheelSgrQueue = queued + `\x1b[<${btn};${pos.col};${pos.row}M`.repeat(ticks);
+    if (this._wheelSgrFlushTimer) return;
+    this._wheelSgrFlushTimer = setTimeout(() => this._flushWheelSgrQueue(), 40);
+  },
+
+  _flushWheelSgrQueue() {
+    this._wheelSgrFlushTimer = null;
+    const data = this._wheelSgrQueue;
+    this._wheelSgrQueue = '';
+    if (data && this.activeSessionId) this._sendInputAsync(this.activeSessionId, data);
+  },
+
+  // Desktop counterpart of the touchend tap branch: hand-encode an SGR report
+  // for a plain left-click when the server strips mouse DECSETs (see
+  // _sessionUsesServerMouseStrip). Every skip below is a click that already has
+  // a meaning elsewhere: synthetic/compat clicks after a touch tap (touchend
+  // reported already), modified clicks (shift keeps xterm's selection
+  // override), double/triple clicks (word/line selection), drag-selections,
+  // clicks on hovered links (activate() already handles the click — a second
+  // synthetic SGR press could e.g. dismiss a claude permission dialog),
+  // clicks outside the cell grid, and sessions where xterm's own encoder is
+  // live (it reported the click itself — a second report would double-move).
+  _handleDesktopTerminalClick(ev) {
+    if (!this.terminal || !ev?.isTrusted) return;
+    if (ev.button !== 0 || ev.detail !== 1) return;
+    if (ev.shiftKey || ev.altKey || ev.ctrlKey || ev.metaKey) return;
+    const mode = this.terminal.modes?.mouseTrackingMode;
+    if (mode && mode !== 'none') return;
+    if (!this._sessionUsesServerMouseStrip()) return;
+    if (this.terminal.hasSelection?.()) return;
+    if (this._linkHovered) return; // link provider hover/leave callbacks (registerFilePathLinkProvider)
+    if (performance.now() <= (this._trustedTapMouseSuppressUntil || 0)) return;
+    if (!ev.target?.closest?.('.xterm-screen')) return;
+    this._sendSyntheticSgrTap(ev.clientX, ev.clientY);
+  },
+
   _installMobileTapMouseGuard() {
     const el = this.terminal?.element;
     if (!el || el._codemanTapMouseGuardInstalled) return;

test/terminal-touch-tap.test.ts

@@ -94,6 +94,308 @@ describe('terminal touch tap mouse guard', () => {
     expect(event.stopImmediatePropagation).not.toHaveBeenCalled();
   });
 
+  it('encodes a tap as an SGR press+release when the server strips mouse DECSETs (claude mode)', () => {
+    const { app } = loadTerminalUiHarness();
+    const sent: Array<{ id: string; data: string }> = [];
+    app.activeSessionId = 'sess-1';
+    app.sessions = new Map([['sess-1', { mode: 'claude' }]]);
+    app._sendInputAsync = (id: string, data: string) => sent.push({ id, data });
+    app.terminal = {
+      cols: 80,
+      rows: 24,
+      element: {
+        querySelector: () => ({ getBoundingClientRect: () => ({ left: 10, top: 20 }) }),
+      },
+      _core: { _renderService: { dimensions: { css: { cell: { width: 8, height: 16 } } } } },
+    };
+
+    expect(app._sessionUsesServerMouseStrip()).toBe(true);
+    // touch at x=10+8*20+1, y=20+16*5+1 → col 21, row 6 (1-based)
+    app._sendSyntheticSgrTap(171, 101);
+
+    expect(sent).toEqual([{ id: 'sess-1', data: '\x1b[<0;21;6M\x1b[<0;21;6m' }]);
+  });
+
+  it('clamps SGR tap coordinates to the terminal grid', () => {
+    const { app } = loadTerminalUiHarness();
+    const sent: string[] = [];
+    app.activeSessionId = 'sess-1';
+    app.sessions = new Map([['sess-1', { mode: 'claude' }]]);
+    app._sendInputAsync = (_id: string, data: string) => sent.push(data);
+    app.terminal = {
+      cols: 80,
+      rows: 24,
+      element: {
+        querySelector: () => ({ getBoundingClientRect: () => ({ left: 0, top: 0 }) }),
+      },
+      _core: { _renderService: { dimensions: { css: { cell: { width: 8, height: 16 } } } } },
+    };
+
+    app._sendSyntheticSgrTap(-50, 99999);
+
+    expect(sent).toEqual(['\x1b[<0;1;24M\x1b[<0;1;24m']);
+  });
+
+  it('does not treat shell sessions as server-mouse-strip mode', () => {
+    const { app } = loadTerminalUiHarness();
+    app.activeSessionId = 'sess-1';
+    app.sessions = new Map([['sess-1', { mode: 'shell' }]]);
+
+    expect(app._sessionUsesServerMouseStrip()).toBe(false);
+  });
+
+  it('desktop click: encodes SGR press+release for a plain left-click in strip mode', () => {
+    const { app } = loadTerminalUiHarness();
+    const sent: Array<{ id: string; data: string }> = [];
+    app.activeSessionId = 'sess-1';
+    app.sessions = new Map([['sess-1', { mode: 'claude' }]]);
+    app._sendInputAsync = (id: string, data: string) => sent.push({ id, data });
+    app.terminal = {
+      cols: 80,
+      rows: 24,
+      modes: { mouseTrackingMode: 'none' },
+      hasSelection: () => false,
+      element: {
+        querySelector: () => ({ getBoundingClientRect: () => ({ left: 10, top: 20 }) }),
+      },
+      _core: { _renderService: { dimensions: { css: { cell: { width: 8, height: 16 } } } } },
+    };
+
+    app._handleDesktopTerminalClick({
+      isTrusted: true,
+      button: 0,
+      detail: 1,
+      clientX: 171,
+      clientY: 101,
+      target: { closest: (sel: string) => (sel === '.xterm-screen' ? {} : null) },
+    });
+
+    expect(sent).toEqual([{ id: 'sess-1', data: '\x1b[<0;21;6M\x1b[<0;21;6m' }]);
+  });
+
+  it('desktop click: skips clicks that already have a meaning elsewhere', () => {
+    const { app } = loadTerminalUiHarness();
+    const sent: string[] = [];
+    app.activeSessionId = 'sess-1';
+    app.sessions = new Map([['sess-1', { mode: 'claude' }]]);
+    app._sendInputAsync = (_id: string, data: string) => sent.push(data);
+    const terminal = () => ({
+      cols: 80,
+      rows: 24,
+      modes: { mouseTrackingMode: 'none' } as { mouseTrackingMode: string },
+      hasSelection: () => false,
+      element: {
+        querySelector: () => ({ getBoundingClientRect: () => ({ left: 0, top: 0 }) }),
+      },
+      _core: { _renderService: { dimensions: { css: { cell: { width: 8, height: 16 } } } } },
+    });
+    const click = (overrides: Record<string, unknown> = {}) => ({
+      isTrusted: true,
+      button: 0,
+      detail: 1,
+      clientX: 50,
+      clientY: 50,
+      target: { closest: (sel: string) => (sel === '.xterm-screen' ? {} : null) },
+      ...overrides,
+    });
+
+    app.terminal = terminal();
+    app._handleDesktopTerminalClick(click({ isTrusted: false })); // synthetic
+    app._handleDesktopTerminalClick(click({ button: 1 })); // middle button
+    app._handleDesktopTerminalClick(click({ detail: 2 })); // double-click word select
+    app._handleDesktopTerminalClick(click({ shiftKey: true })); // selection override
+    app._handleDesktopTerminalClick(click({ target: { closest: () => null } })); // outside grid
+
+    app.terminal = { ...terminal(), hasSelection: () => true }; // drag-selection just ended
+    app._handleDesktopTerminalClick(click());
+
+    app.terminal = { ...terminal(), modes: { mouseTrackingMode: 'vt200' } }; // xterm encoder live
+    app._handleDesktopTerminalClick(click());
+
+    app.terminal = terminal();
+    app.sessions = new Map([['sess-1', { mode: 'shell' }]]); // not a strip mode
+    app._handleDesktopTerminalClick(click());
+
+    expect(sent).toEqual([]);
+  });
+
+  it('desktop click: skips the click while a terminal link is hovered (activate() handles it)', () => {
+    const { app } = loadTerminalUiHarness();
+    const sent: string[] = [];
+    app.activeSessionId = 'sess-1';
+    app.sessions = new Map([['sess-1', { mode: 'claude' }]]);
+    app._sendInputAsync = (_id: string, data: string) => sent.push(data);
+    app.terminal = {
+      cols: 80,
+      rows: 24,
+      modes: { mouseTrackingMode: 'none' },
+      hasSelection: () => false,
+      element: {
+        querySelector: () => ({ getBoundingClientRect: () => ({ left: 0, top: 0 }) }),
+      },
+      _core: { _renderService: { dimensions: { css: { cell: { width: 8, height: 16 } } } } },
+    };
+    const click = {
+      isTrusted: true,
+      button: 0,
+      detail: 1,
+      clientX: 50,
+      clientY: 50,
+      target: { closest: (sel: string) => (sel === '.xterm-screen' ? {} : null) },
+    };
+
+    app._linkHovered = true; // link provider hover() fired — this click opens the link
+    app._handleDesktopTerminalClick(click);
+    expect(sent).toEqual([]);
+
+    app._linkHovered = false; // leave() fired — plain clicks report again
+    app._handleDesktopTerminalClick(click);
+    expect(sent).toEqual(['\x1b[<0;7;4M\x1b[<0;7;4m']);
+  });
+
+  it('desktop click: skips the compat click that follows a touch tap', () => {
+    const { app, setNow } = loadTerminalUiHarness();
+    const sent: string[] = [];
+    app.activeSessionId = 'sess-1';
+    app.sessions = new Map([['sess-1', { mode: 'claude' }]]);
+    app._sendInputAsync = (_id: string, data: string) => sent.push(data);
+    app.terminal = {
+      cols: 80,
+      rows: 24,
+      modes: { mouseTrackingMode: 'none' },
+      hasSelection: () => false,
+      element: {
+        querySelector: () => ({ getBoundingClientRect: () => ({ left: 0, top: 0 }) }),
+      },
+      _core: { _renderService: { dimensions: { css: { cell: { width: 8, height: 16 } } } } },
+    };
+    const click = {
+      isTrusted: true,
+      button: 0,
+      detail: 1,
+      clientX: 50,
+      clientY: 50,
+      target: { closest: (sel: string) => (sel === '.xterm-screen' ? {} : null) },
+    };
+
+    app._suppressTrustedTapMouseEvents(); // touchend just handled the tap
+    app._handleDesktopTerminalClick(click);
+    expect(sent).toEqual([]);
+
+    setNow(10_000); // window expired — a genuine mouse click reports again
+    app._handleDesktopTerminalClick(click);
+    expect(sent).toEqual(['\x1b[<0;7;4M\x1b[<0;7;4m']);
+  });
+
+  it('tap: does nothing while the viewport is scrolled up into local scrollback', () => {
+    const { app } = loadTerminalUiHarness();
+    const sent: string[] = [];
+    app.activeSessionId = 'sess-1';
+    app.sessions = new Map([['sess-1', { mode: 'claude' }]]);
+    app._sendInputAsync = (_id: string, data: string) => sent.push(data);
+    app.terminal = {
+      cols: 80,
+      rows: 24,
+      buffer: { active: { viewportY: 10, baseY: 50 } }, // scrolled up
+      element: {
+        querySelector: () => ({ getBoundingClientRect: () => ({ left: 0, top: 0 }) }),
+      },
+      _core: { _renderService: { dimensions: { css: { cell: { width: 8, height: 16 } } } } },
+    };
+
+    app._sendSyntheticSgrTap(50, 50);
+    expect(sent).toEqual([]);
+
+    app.terminal.buffer.active.viewportY = 50; // back at the bottom
+    app._sendSyntheticSgrTap(50, 50);
+    expect(sent).toEqual(['\x1b[<0;7;4M\x1b[<0;7;4m']);
+  });
+
+  it('wheel: forwards to the app only for verified sessions at the buffer bottom without Shift', () => {
+    const { app } = loadTerminalUiHarness();
+    app.activeSessionId = 'sess-1';
+    app.sessions = new Map([['sess-1', { mode: 'claude', cliVersion: '2.1.187' }]]);
+    app.terminal = {
+      modes: { mouseTrackingMode: 'none' },
+      buffer: { active: { viewportY: 50, baseY: 50 } },
+    };
+
+    expect(app._shouldForwardWheelToApp({ shiftKey: false })).toBe(true);
+    expect(app._shouldForwardWheelToApp({ shiftKey: true })).toBe(false); // Shift = local scrollback
+
+    app.terminal.buffer.active.viewportY = 10; // browsing local scrollback
+    expect(app._shouldForwardWheelToApp({ shiftKey: false })).toBe(false);
+    app.terminal.buffer.active.viewportY = 50;
+
+    app.terminal.modes.mouseTrackingMode = 'vt200'; // xterm's own encoder live
+    expect(app._shouldForwardWheelToApp({ shiftKey: false })).toBe(false);
+    app.terminal.modes.mouseTrackingMode = 'none';
+
+    app.sessions = new Map([['sess-1', { mode: 'shell' }]]); // not a strip mode
+    expect(app._shouldForwardWheelToApp({ shiftKey: false })).toBe(false);
+  });
+
+  it('wheel: gates claude forwarding on CLI version 2.1.187+ (unknown or older stays local)', () => {
+    const { app } = loadTerminalUiHarness();
+    app.activeSessionId = 'sess-1';
+    app.terminal = {
+      modes: { mouseTrackingMode: 'none' },
+      buffer: { active: { viewportY: 50, baseY: 50 } },
+    };
+    const withVersion = (cliVersion?: string) => {
+      app.sessions = new Map([['sess-1', { mode: 'claude', cliVersion }]]);
+      return app._shouldForwardWheelToApp({ shiftKey: false });
+    };
+
+    expect(withVersion(undefined)).toBe(false); // banner not parsed yet → assume older
+    expect(withVersion('2.1.186')).toBe(false); // last version whose menus capture wheel
+    expect(withVersion('2.1.187')).toBe(true); // first version verified safe
+    expect(withVersion('2.2.0')).toBe(true);
+    expect(withVersion('3.0.0')).toBe(true);
+    expect(withVersion('garbage')).toBe(false); // unparseable → assume older
+  });
+
+  it('wheel: codex forwards without a version; gemini never forwards', () => {
+    const { app } = loadTerminalUiHarness();
+    app.activeSessionId = 'sess-1';
+    app.terminal = {
+      modes: { mouseTrackingMode: 'none' },
+      buffer: { active: { viewportY: 50, baseY: 50 } },
+    };
+
+    app.sessions = new Map([['sess-1', { mode: 'codex' }]]); // verified TUI, no version gate
+    expect(app._shouldForwardWheelToApp({ shiftKey: false })).toBe(true);
+
+    app.sessions = new Map([['sess-1', { mode: 'gemini', cliVersion: '9.9.9' }]]); // unverified TUI
+    expect(app._shouldForwardWheelToApp({ shiftKey: false })).toBe(false);
+  });
+
+  it('wheel: encodes SGR 64/65 ticks, caps per event, and coalesces into one flush', () => {
+    const { app } = loadTerminalUiHarness();
+    const sent: Array<{ id: string; data: string }> = [];
+    app.activeSessionId = 'sess-1';
+    app.sessions = new Map([['sess-1', { mode: 'claude' }]]);
+    app._sendInputAsync = (id: string, data: string) => sent.push({ id, data });
+    app.terminal = {
+      cols: 80,
+      rows: 24,
+      element: {
+        querySelector: () => ({ getBoundingClientRect: () => ({ left: 0, top: 0 }) }),
+      },
+      _core: { _renderService: { dimensions: { css: { cell: { width: 8, height: 16 } } } } },
+    };
+
+    app._sendSyntheticSgrWheel(50, 50, -2); // 2 ticks up
+    app._sendSyntheticSgrWheel(50, 50, 9); // capped at 5 ticks down
+    expect(sent).toEqual([]); // nothing until the flush timer fires
+
+    app._flushWheelSgrQueue();
+    expect(sent).toEqual([{ id: 'sess-1', data: '\x1b[<64;7;4M'.repeat(2) + '\x1b[<65;7;4M'.repeat(5) }]);
+
+    app._flushWheelSgrQueue(); // queue drained — no duplicate send
+    expect(sent).toHaveLength(1);
+  });
+
   it('allows trusted mouse events after the tap window expires', () => {
     const { app, setNow } = loadTerminalUiHarness();
     const { element, dispatch } = createElementHarness();